*: pivot everything to OpenGL ES 2.0

In the interests of keeping things bisectable this is one big commit of
everything necessary to go from OpenGL 2.1 to OpenGL ES 2.0 in one fell
swoop.

There's a handful of annoying mechanical changes necessary in shaders like
removing the 'f' suffix on float constants e.g. 1.f becomes 1.0 etc.

This is primarily happening to enable emscripten builds

1 files changed, 18 insertions, 13 deletions

diff --git a/src/plasma-node.c b/src/plasma-node.c
index 1eb4c7a..0ad8752 100644
--- a/src/plasma-node.c
+++ b/src/plasma-node.c
@@ -26,50 +26,55 @@
 
 
 static const char	*plasma_vs = ""
-	"#version 120\n"
+	"#version 100\n"
 
 	"uniform mat4	projection_x;"
 
 	"attribute vec3 vertex;"
 	"attribute vec2 texcoord;"
 
+	"varying vec2 UV;"
+
 	"void main()"
 	"{"
-	"	gl_TexCoord[0].xy = texcoord;"
-	"	gl_Position = projection_x * vec4(vertex, 1.f);"
+	"	UV = texcoord;"
+	"	gl_Position = projection_x * vec4(vertex, 1.0);"
 	"}"
 "";
 
 
 // derived from https://www.bidouille.org/prog/plasma
 static const char	*plasma_fs = ""
-	"#version 120\n"
+	"#version 100\n"
 
 	"#define PI 3.1415926535897932384626433832795\n"
 
+	"precision mediump float;"
 	"uniform float alpha;"
 	"uniform float time;"
 
+	"varying vec2 UV;"
+
 	"void main() {"
 	"	float v;"
-	"	float stime = sin(time * .01f) * 100.f;"
+	"	float stime = sin(time * .01) * 100.0;"
 
-	"	vec2 c = gl_TexCoord[0].st;"
+	"	vec2 c = UV;"
 
 	// this zooms the texture coords in and out a bit with time
-	"	c *= (sin(stime * .01f) *.5f + .5f) * 3.f + 1.f;"
+	"	c *= (sin(stime * .01) *.5 + .5) * 3.0 + 1.0;"
 
 	// plasma calculations, stime instead of time directly to vary directions and speed
 	"	v = sin((c.x + stime));"
-	"	v += sin((c.y + stime) * .5f);"
-	"	v += sin((c.x + c.y +stime) * .5f);"
+	"	v += sin((c.y + stime) * .5);"
+	"	v += sin((c.x + c.y +stime) * .5);"
 
-	"	c += vec2(sin(stime * .33f), cos(stime * .5f)) * 3.f;"
+	"	c += vec2(sin(stime * .33), cos(stime * .5)) * 3.0;"
 
-	"	v += sin(sqrt(c.x * c.x + c.y * c.y + 1.f) + stime);"
+	"	v += sin(sqrt(c.x * c.x + c.y * c.y + 1.0) + stime);"
 
-	"	vec3 col = vec3(cos(PI * v + sin(time)), sin(PI * v + cos(time * .33f)), cos(PI * v + sin(time * .66f)));"
-	"	gl_FragColor = vec4(col * .5f + .5f, alpha);"
+	"	vec3 col = vec3(cos(PI * v + sin(time)), sin(PI * v + cos(time * .33)), cos(PI * v + sin(time * .66)));"
+	"	gl_FragColor = vec4(col * .5 + .5, alpha);"
 	"}"
 "";